HIGH-TEMPERATURE REMOTE THERMOMETRY USING LASER-INDUCED FLUORESCENCE DECAY LIFETIME MEASUREMENTS OF Y2O3-EU AND YAG-TB THERMOGRAPHIC PHOSPHORS

A Nd: YAG laser-based remote sensing system, for determining the surface temperature of substrates coated with thermographic phosphors, has been developed. The obtained fluorescence decay lifetime versus temperature measurements for Y2O3: Eu (4.52% Eu) and YAG: Tb (5% Tb) over the temperature range 27-1095-degrees-C are presented. Both phosphors can be used for continuous temperature measurements over the range approximately 550-degrees-C- approximately 1000-degrees-C. In addition, stepwise regression analysis is used to calculate empirical relationships expressing temperature as a function of the measured fluorescence lifetimes for both phosphors beyond the onset temperature quenching point. The accuracy of the temperature measurements was estimated to be +/- 5%. Furthermore, a comparison between the intensity of the 611 nM-Y2O3: Eu and the 544 nm-YAG: Tb emission lines as a function of temperature is presented.